Centrifugal governor for motors



May 3, 1949. V; c. KENNEDY CENTRIFUGAL GOVERNOR FOR MOTORS Original Filed Oct. 9

m'v NTO R Ian/v: C. kemvzo ATTORNEY Patented May 3,' 1949 UNITED STATES PATENT OFFICE CENTRIFUGAL GOVERNOR FOR MOTORS Verne 0. Kennedy, Evanston, Ill., assignor to Dormeyer Corporation, Chicago, 111., a corporation of Illinois Original application October 9, 1942, Serial No.

Divided and this application March 23, 1945, Serial No. 584,294

7 Claims. (01. 318-325) vide an improved centrifugal speed governor wherein a self-contained body of fluid is employed as the centrifugated element.

Another object of the invention is to locate the self-contained body of speed governor fluid in the path of incoming cooling air for a power unit before the air is subjected to the varying heat of the power unit.

Another object of the invention is to provide a speed governor having a centrifugally influenced fluid which operates uniformly at all times independently of motor heat.

Another object of the invention is to provide an improved cooling system and an arrangement for fractional horse power motors wherein electrical accessoriesto the motor, such as the condenser, interrupter, and resistance for a speed governor are located outside the path of air passing through the motor, and along with the transmission are mounted within a finishing shell and cooled with a continuous bath of air by the same fan cooling the motor.

These being among the objects of the invention, other and further objects will become apparent from the drawings, the description relating thereto, and the appended claims.

Referring now to the drawings, v

The figure is a fragmentary sectional view in which the section is taken vertically through the longitudinal center of a food mixer illustrating an embodiment of the present invention.

Referring now to the drawings in further detail, the power unit I is shown disposed in its working position as mounted upon the support II to overhang a bowl l2 rotatably mounted on a turntable l3. The turntable I3 is pivoted as at II on the base l5 and the lower end of the support is rigidly secured to the base as at IS in a suitable manner. When the unit is in its working position the heaters [1, preferably interdigitating beaters, depend and are disposed in the bowl to agitate the contents thereof.

A handle I8 is releasably secured to the power unit, and at its forward end conceals in mutually supporting relationship the front end of the power takeoif socket 20 where it extends through the shell 2| for this purpose. Removal of the handle provides access to the juicer attachment shown in phantom 22, or a meat chopper shown in phantom 23.

Power unit The power unit [0 comprises the shell 2|, a prime mover 24', a transmission 25, the removable handle I8, just mentioned, a speed governor 26, and preferably two downwardly extending parallel flanges 21 upon the shell 2i spaced from each other to straddle and receive the top of the support I 1.

Prime mover Briefly stated, the prime mover 24 in turn comprises a stator 28 and a rotor or armature 30 supspaced end members 33 and 34, one of which 34 is a part of or is secured to the transmission 25.

Self aligning armature bearings 35 are mounted in the end members and a brush holder 36 is also carried by the bolts and spacers where the brushes 3! may cooperate in the usual manner with the commutator 38.

As more particularly shown in Fig. 1 the rear end member 33 is a stamped plate having a central opening 40 and laterally spaced openings 4| to receive the ends of the bolts, and is provided with arcuate perforations 42 which allow for the passage of air through the end member.

The bearing 35 has a preferably spherical or rounded contour over a portion of its outer sur-' face, which portion has a greater diameter than the opening 40 so that the bearing can be disposed to rest and be supported in the opening where it is held in place by a stamped retainer 43 riveted to the end member as at 44.

Speed governor The speed governor 26 is mounted on the end of the armature shaft 63 where it extends beyond the rear bearing 35 and comprises a centrifugally responsive device, two contacts I4 and 65 carried by the spring arms BI and 62 that are mounted at spaced points upon the insulating member just mentioned, and an adjustable element 63 for varying the position of the arm 82 in relationship to the arm 6|.

The responsive device comprises a circular plate 6! provided with radially disposed vanes 88 upon one side. Over the vanes is secured marginally. as by brazing, a cup-shaped member 10 having a flexing end wall and a bellows type side wall 3 12 so that the center of the end wall and the side wall flex independently of each other.

A spring I3 is disposed between the plate and the end wall at the axis of rotation to urge the center of the end wall away from the plate. The exposed face of the end wall receives a. conical end thrust member 14 whose apex is disposed at the axis of rotation and engages the spring arm 6| under the tension present in the spring arm and under that which is created by the spring. The conical member is held in place permanently as by brazing.

The plate is slightly concave and is provided with an opening 15 at the center of the concavity and a cylindrical flange 16 by which it is mounted upon the shaft. The space between the plate and member is filled with a liquid 11, preferably an oil, and allrthe air is permitted to escape through the opening 15. During filling operation the spring 13 will have expanded the compartment quite measurably and after all the air is replaced with oil the assembly is placed in a form and collapsed to an exact extent to'remove surplus oil from the compartment, after which the opening 15 is sealed.

Thereafter, when released from the form the expansion force exerted by the spring 13 will force the point of the member 14 outwardly and collapse the side wall bellows l2 inwardly. When the device'is rotated by the motor shaft the oil 11 in the compartment centrifugates to expand the side wall bellows 12 under the influence of which the end wall is drawn inwardly at the center. The vanes 68 keep the contents-of the compartment in step with the speed of rotation of the shaft 53 and in order to accentuate their action the position of the vanes may be such that they are canted slightly from radially with the outer edge trailing a true radius. With this arrangement, as the motor speeds up the vanes will tend to force the oil outwardly and as the motor slows down the oil will overtake the vanes and be moved by them inwardly. As the motor slows down the reverse will take place, thereby inducing a relative axial movement of the bearing point in relationship to variations in the speed of the motor.

' This relative movement of the bearing point is used to control the make and break of the contacts 64 and 65. The contact 65 is adjusted by the cam represented diagrammatically at 65 to vary the point in the speed curve of the motor at which a break between the contacts 64 and 65 takes place. These contacts comprise a switch connected in series with the motor windings and in parallel with a condenser 18 and a resistance 80 that cushions the electrical drop in the motor circuit when the contacts are separated and also to suppress radio interference.

The cam control 66 may be operated from outside the housing in any suitable manner and upon the housing may be printed or inscribed instructions or indices (not shown) to assist the operator in selecting the speed adjustment he or she might desire. A start and stop switch (not shown) is controlled by the same shaft as the cam to open at the low point on the speed curve of the motor. This switch may be either a separate switch or the governor contacts 64 and G5 themselves. If the governor contacts are utilized then a suitable construction upon the cam which comes into operation at a predetermined point 4 of rotation of the cam will accomplish the result desired.

Thus, from the description had and the designation oi the operations performed, it will be seen that the objects and purposes mentioned and claimed herein are accomplished by the embodiment deflned, and although the description has been lodged in terms somewhat speciflc in details for a better understanding of the embodiment illustrated, the several embodiments of the invention suggested and described will be apparent to those skilled in the art that various and further uses, modifications and changes may be made without departing from the spirit and substance of the invention, the scope of which is commensurate with the appended claims.

What is claimed is:

1. In a controlling switch or a power unit for food mixers, a rotatable envelope having a closed body of liquid therein and a, flexible wall, a switch in circuit with the power unit, and means interconnecting said wall and switch for controlling the switch in relation to movement of the wall.

2. A speed control for a food mixer power unit comprising a rotating envelope having a closed body of liquid therein and a flexible wall, means for urging the wall in one direction, centrifugation of the liquid in the envelope urging the wall in the opposite direction, a switch, and means interconnecting said switch and wall for operating the switch in relationship to the movement of said wall.

3. A speed governor for a motor comprising an envelope rotatable by a prime mover, said envelope having a body of liquid therein centrifugated by rotation of said envelope, said envelope including a wall flexing under the influence oi the liquid when centrifugated, means opposing said flexing, and a switch in the circuit of the prime mover actuated by said flexing wall.

4. A power unit for a food mixer comprising a a prime mover, a shell for said prime mover, an apertured partition in said shell, means for forcing air through the partition for cooling the prime mover, a speed governor connected in series with the prime mover including a rotating envelope having a body of liquid therein subject to centriiugation, said governor being located on the intake side of said apertures where the temperature of the cooling air is substantially constant.

5. A power unit for a food mixer comprising a prime mover, a shell for said prime mover, electrical resistance means connected in circuit with the prime mover mounted within said shell, an apertured partition in said shell, means for forcing air through the partition for cooling-the prime mover, a speed governor connected in series with the resistance means including a rotating envelope having a body of liquid therein subject to centrifugation, said governor being located on the intake side of said apertures where the tem perature of the cooling air is substantially constant, and said resistance being located on the outlet side of the apertures out of the pathoi air moving into direct contact with the prime mover.

6. A speed governor for a motor comprising an envelope rotatable by a prime mover, radially extending vanes carried by and disposed within said envelope, said envelope having a body of liquid therein in contact with said vanes and centrifugated by rotation of said envelope and vanes, and a wall flexing under the influence of the liquid when centrifugated, means opposing said flexing, and a-switch in the circuit of the prime mover actuated by said flexing wall.

7. A speed governor for a motor comprising an envelope rotatable by a. prime mover, vanes in said envelope that are canted slightly with their outer edges trailing a true radius, and a, .body of liquid in said envelope surrounding the vanes centritugated by rotation of said envelope, said envelope including a wall flexing under the influence oi the liquid when centrifugated, means opposing said flexing, and a switch in the circuit of the prime mover actuated by said flexing wall.

VERNE C. KENNEDY.

6 nnrnnnncns crrnn The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date 1,222,985 Pharo Apr. 17, 1917 1,392,890 Fulton Oct. 4, 1921 2,092,955 Chamberlain Sept. 14, 1937 2,106,058 Nielsen et al Jan. 18, 1938 2,357,190 Holst Aug. 29, 1944 

